Mesoscopic dynamics of complex vesicle formation: kinetic versus thermodynamic factors

Abstract

We have used dynamic self-consistent field (DSCF) theory to elaborate on our previous study of spontaneous vesicle formation in short amphiphilic systems (G.J.A. Sevink and A.V. Zvelindovsky, Macromolecules 2005, 38, p. 7502). Here, we focus on the situation where a spherical shape, representing the macrostructure, is imposed from the start. Inside this droplet-like container, the solphophilic and solphophobic blocks are initially mixed. Such experimental starting conditions can be obtained with inktjet techniques, where a droplet of amphiphiles is quenched in solvent. In particular, we consider the interplay between confinement and microstructure for a single droplet. We show that there is a dependency on droplet/cluster size. Large spherical amphiphilic droplets are only favored in case of symmetric amphiphiles, and very asymmetric amphiphiles are rather indifferent of the initial droplet shape. Slightly asymmetric systems prefer larger macrostructures that are non-spherical. We considered mixing of systems with different interfacial properties in detail by induced fusion of droplets of different material, leading to janus-like vesicles. A detailed analysis by means of Minkowski functionals hints once more that most processes in these systems are curvature driven.